Prior-art waveguide devices, including but not limited to an Ortho-Mode Transducer (OMT), polarizer, filter, and feed horn use air trapped in hollow internal cavities as a dielectric. The internal cavities are surrounded by conductive walls typically made of metals. The RF waves travel through air, the dielectric, in the cavities of these devices, and are bounced back or reflected by the conductive walls defining the cavities.
FIG. 1A and FIG. 1B illustrate a prior art disassembled waveguide, an Ortho-Mode Transducer (OMT), defining a cavity for waveguide propagation through a dielectric of air according to various embodiments.
FIG. 2A and FIG. 2B illustrate a prior art disassembled waveguide, a polarizer, defining a cavity for waveguide propagation through a dielectric of air according to various embodiments.
FIG. 3A and FIG. 3B illustrate a prior art disassembled waveguide, a bandpass filter, defining a cavity for waveguide propagation through a dielectric of air according to various embodiments.
As illustrated by FIG. 1A, FIG. 1B, FIG. 2A, FIG. 2B, FIG. 3A and FIG. 3B, most waveguide devices are not manufactured as a single piece. Instead, the waveguide devices have to be manufactured in two or more pieces, typically using either machining, injecting or die-casting. The two or more pieces are then assembled into a final device. The final device has disadvantages including high costs associated with die-casting, higher costs of assembling, and difficulties in precisely aligning the two or more pieces. This is an increasing problem as the operating frequency is increased.
Additionally, the prior art devices use air as a dielectric, in other words, the air disposed in cavities defined by metal enclosures. Features of the waveguide are defined in the cavity-facing surfaces of the metal enclosure. The radio frequency waves propagated through the waveguide, travel in the air and bounce off the metal surfaces of the enclosure, and are thus affected by the waveguide device. As such, the radio frequency waves are manipulated by the metal boundary conditions of the metal enclosure around the cavity containing the air (dielectric). Moreover, these devices are bulky—physically large. The bulkiness hinders the miniaturization of the final products, such as, a fixed Very Small Aperture Terminal (VSAT), or a mobile VSAT.